1. Field of the Invention
The present invention relates to a light emitting display device and a method of driving the same, and more particularly to, a light emitting display device capable of controlling brightness in accordance with brightness of peripheral light and the total amount of emission of a display region and a method of driving the same.
2. Discussion of Related Art
Recently, various small and light flat panel displays (FPD) having reduced weight and volume that overcome the disadvantages of cathode ray tubes (CRT) have been developed. In particular, light emitting display devices having high emission efficiency, brightness, viewing angles, and response speed are in the spotlight.
Light emitting display devices can be classified as an organic light emitting display device using organic light emitting diodes (OLEDs) and an inorganic light emitting display device using inorganic light emitting diodes. An OLED includes an anode electrode, a cathode electrode, and an organic emission layer positioned between the anode electrode and the cathode electrode to emit light by combination of electrons and holes. The inorganic light emitting diode referred to as a light emitting diode (LED) includes an inorganic emission layer, for example, an emission layer formed of a PN junction of semiconductor material unlike the OLED.
FIG. 1 illustrates the structure of a conventional light emitting display device.
Referring to FIG. 1, the conventional light emitting display device includes a display region 10, a power source supply unit 30, a scan driver 40, and a data driver 50.
The display region 10 includes n×m pixels 5 each including an electroluminescent (EL) device (or light emitting device, not shown), n scan lines S1, S2, . . . , and Sn and n emission control lines E1, E2, . . . , and En formed in a row direction to respectively transmit scan signals and emission control signals, and m data lines D1, D2, . . . , and Dm formed in a column direction to transmit data signals. The display region 10 emits light from the EL devices (not shown) using the scan signals, the emission control signals, and the data signals to display images.
The power source supply unit 30 provides a first power source ELVdd and a second power source ELVss having a potential lower than the potential of the first power source ELVdd, to the display region 10 so that currents corresponding to the data signals flow to pixels 5, respectively, in accordance with a difference in voltage between the first power source ELVdd and the second power source ELVss.
The scan driver 40 outputs scan signals to apply the scan signals to the scan lines S1, S2, . . . , and Sn and outputs emission control signals to apply the emission control signals to the emission control lines E1, E2, . . . , and En.
The data driver 50 is connected to the data lines D1, D2, . . . , and Dm to apply the data signals to the display region 10.
According to the conventional light emitting display device having the above structure, the pixels 5 emit light at uniform brightness regardless of peripheral brightness, which is the brightness of peripheral light (i.e., light of a region around the display). Therefore, when the same gray scales are displayed, the clarity of the image displayed when the peripheral brightness is high is less than the clarity of the image displayed when the peripheral brightness is low. Also, when many pixels 5 emit light with high brightness in the light emitting display device, the amount of current supplied to the display region 10 increases so that heavy load is applied to the power source supply unit 30, thereby requiring the power source supply unit 30 to provide high output.